Seventies of the twentieth century. In the basement of the family home in Copenhagen, Simon Pasternak opens an old suitcase that belonged to his maternal grandmother's brother, Dirk-Ingvar Bonnek, a soldier who disappeared in Ukraine in World War II in 1943. To his surprise, the young finds documents with runes of the SS and a dagger of this same organization. It is the hidden trace of a Dane who, after the Nazi occupation of his country, ran to volunteer to help them. "Was there an executioner behind the endearing grandfather?" asks historian David Alegre Lorenz, author of the essay Collaborators...